Great thinking btrcop - I'm going to make one myself. Thanks for posting.
I had the same chirruping after about 1500 miles, and decided to check the belt tension. My technique was embarrassingly crude by comparison - I hung 10lbs of roofing lead from middle of the belt and measured the deflection with a steel rule taped to the swing arm! Still, it worked and thanks also to some PTFE spray I now have a silent belt.